By Nancy Bowers, BSN, MPH
Chances are you know someone who is allergic to peanuts, perhaps even someone in your family. And it’s no wonder, with the continuing rise in this very serious food allergy. Although the prevalence varies by worldwide geography and culture, as many as 8 percent of children and 2 percent of adults are affected in the United States. And the rate is rising. Between 1997 and 2002, the number of children with peanut allergy under age 5 doubled. So interest and concern is growing among teachers, daycare providers, health care professionals, and, of course, parents.
Which foods cause allergies?
Peanuts are one of the eight foods that cause 90 percent of all food-allergic reactions. The others are milk, egg, tree nut (pecan, cashew, etc.), fish, shellfish, soy, and wheat. For people with true food allergies, ingesting even a small amount of the food can be serious and even fatal.
Peanut allergies are some of the most severe, and because peanuts are so common in our food culture, the potential for accidental ingestion is high. Peanut allergy is responsible for more deaths than any other type of allergy. And unlike some other foods, only about 20 percent of children outgrow a peanut allergy. To complicate matters, many peanut-allergic people are also allergic to tree nuts and other legumes. (Peanuts are not true nuts but are legumes, related to lentils, peas and soy).
What causes peanut allergy?
Peanut allergy arises from both genetic and environmental factors. Like other allergies, a food allergy is more common when other family members have atopic disease, especially those with eczema and asthma. Studies of twins have found a strong genetic influence. But sometimes, there is no apparent family history. For peanut allergy to develop, there is an initial exposure that causes sensitization. Studies are unclear as to when this occurs. Some research has suggested that peanuts in the mother’s diet during pregnancy and breastfeeding plays a role. A recent European study linked expectant mothers’ consumption of nuts and peanuts with an increased risk of asthma in their children. However, other studies suggest that pregnant women who avoid eating peanuts can actually increase the chances of allergy in their children.
Peanut proteins do cross into breastmilk, although research has not shown a clear link between breastmilk exposure and peanut allergy in children. There is also evidence of cross-sensitivity to soy-based formulas. Other routes of exposure can include use of skin creams containing peanut oils. It isn’t clear if waiting until children are at least 2 or 3 years old before introducing peanuts and other allergenic foods can decrease the risk of allergy. Some experts believe this may actually increase a child’s risk for a food allergy, because it prevents the child from building up a natural tolerance to the food—an immune process that begins early in life.
What happens?
The first time a food is eaten, the allergic person’s immune system mistakenly sees the food as dangerous and creates specific antibodies to the food. When the food is eaten the next time, the immune system releases large amounts of chemical substances, including histamine, to protect the body. This triggers allergic symptoms throughout the body, in the respiratory system, gastrointestinal tract, skin, and even the cardiovascular system. This is called an anaphylactic reaction. Symptoms can include rash/hives, abdominal pain, mouth and throat swelling, wheezing, drop in blood pressure, and heart arrhythmias. This is an emergency and requires immediate medical treatment.
It is hard to predict each person’s sensitivity to peanuts. For most people, severe reactions can occur after ingesting even small amounts. For others, casual contact, such as touching contaminated tables or being in the same room with peanuts can cause symptoms. The US now has labeling laws for all commercially processed foods requiring manufacturers to disclose major food allergens. However, even if peanuts are not listed as a main ingredient, there are risks of contamination when labels state “may contain peanuts” or ‘‘made in a factory that also processes peanuts.’’
What can you do?
If you’re pregnant, talk with your physician about your family history of allergy and asthma. You may want to consider avoiding peanuts if your risks are high. Exclusive breastfeeding for at least 3 months helps protect against childhood wheezing and possibly the development of asthma. The American Academy of Pediatrics recommends continuing breastfeeding for at least the first year. Wait until your baby is at least 4 to 6 months old before introducing sold foods.
If you have a child with peanut allergy, become informed, and educate those who care for your child. Strict avoidance of foods that contain peanuts or peanut products is the only way to avoid a reaction. Reading ingredient labels for all foods is critical. And, since manufacturers frequently change processing, it’s important to read labels every time, even on tried and true products. Watch for risky situations (birthday parties, Asian and exotic foods), hidden ingredients, and cross-contamination (using the same utensil for multiple foods). You might want to consider a medical-alert bracelet for your child. Be prepared for an emergency. You’ll need to have on hand antihistamines such as Benadryl, and epinephrine, in injectable form such as EpiPen, and know how and when to use these.
For more information see:
Food Allergy & Anaphylaxis Network
American Academy of Allergy, Asthma & Immunology
American College of Allergy, Asthma & Immunology
Academy of Pediatrics
About the Author
Nancy is the founder of Marvelous Multiples and the mother of a peanut-allergic child. Her son (a fraternal twin) was diagnosed at one year of age, after a reaction to eating a tiny piece of peanut butter cracker. Interestingly, his twin sister has no allergies, and there is no known family history of food allergy. Her son is now 18 years old, and fortunately has never had a serious reaction. But Nancy cautions, “We have also been extremely vigilant about food and have been strong advocates in educating family, friends, and teachers.”